What Causes Drowsiness, Chills And Fever While On Flagyl?

I was prescribed flagyl to take for a week prior to having a colonoscopy. After the first 3 doses on the first day, I had various symptoms including being very sleepy,chills and then waking feeling feverish. waking up with metallic taste in my mouth , feeling nauseous, no appetite, feeling disoriented and fearful, headache., I took the next day and felt more sleepy had two naps of 2-3 hours and could not eat. Also bloody stool. Tried to call my Dr. and then passed on to two others covering for the holiday, but no response. The colonoscopy is planned for Sept. 9, but I ve stopped taking flagyl. I feel much better, but since I can t reach my Dr. until two days from now I d like to know if I ve done the right thing.